/*  Copyright (C) 2014-2021 FastoGT. All right reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

        * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following disclaimer
    in the documentation and/or other materials provided with the
    distribution.
        * Neither the name of FastoGT. nor the names of its
    contributors may be used to endorse or promote products derived from
    this software without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#pragma once

#include <common/string16.h>

namespace common {
namespace uri {

// Component ------------------------------------------------------------------

// Represents a substring for URL parsing.
struct Component {
  Component() : begin(0), len(-1) {}

  // Normal constructor: takes an offset and a length.
  Component(int b, int l) : begin(b), len(l) {}

  int end() const { return begin + len; }

  // Returns true if this component is valid, meaning the length is given. Even
  // valid components may be empty to record the fact that they exist.
  bool is_valid() const { return (len != -1); }

  // Returns true if the given component is specified on false, the component
  // is either empty or invalid.
  bool is_nonempty() const { return (len > 0); }

  void reset() {
    begin = 0;
    len = -1;
  }

  bool operator==(const Component& other) const { return begin == other.begin && len == other.len; }

  int begin;  // Byte offset in the string of this component.
  int len;    // Will be -1 if the component is unspecified.
};

// Helper that returns a component created with the given begin and ending
// points. The ending point is non-inclusive.
inline Component MakeRange(int begin, int end) {
  return Component(begin, end - begin);
}

// Parsed ---------------------------------------------------------------------

// A structure that holds the identified parts of an input URL. This structure
// does NOT store the URL itself. The caller will have to store the URL text
// and its corresponding Parsed structure separately.
//
// Typical usage would be:
//
//    Parsed parsed;
//    Component scheme;
//    if (!ExtractScheme(url, url_len, &scheme))
//      return I_CAN_NOT_FIND_THE_SCHEME_DUDE;
//
//    if (IsStandardScheme(url, scheme))  // Not provided by this component
//      ParseStandardURL(url, url_len, &parsed);
//    else if (IsFileURL(url, scheme))    // Not provided by this component
//      ParseFileURL(url, url_len, &parsed);
//    else
//      ParsePathURL(url, url_len, &parsed);
//
struct Parsed {
  // Identifies different components.
  enum ComponentType {
    SCHEME,
    USERNAME,
    PASSWORD,
    HOST,
    PORT,
    PATH,
    QUERY,
    REF,
  };

  // The default constructor is sufficient for the components, but inner_parsed_
  // requires special handling.
  Parsed();
  Parsed(const Parsed&);
  Parsed& operator=(const Parsed&);
  ~Parsed();

  // Returns the length of the URL (the end of the last component).
  //
  // Note that for some invalid, non-canonical URLs, this may not be the length
  // of the string. For example "http://": the parsed structure will only
  // contain an entry for the four-character scheme, and it doesn't know about
  // the "://". For all other last-components, it will return the real length.
  int Length() const;

  // Returns the number of characters before the given component if it exists,
  // or where the component would be if it did exist. This will return the
  // string length if the component would be appended to the end.
  //
  // Note that this can get a little funny for the port, query, and ref
  // components which have a delimiter that is not counted as part of the
  // component. The |include_delimiter| flag controls if you want this counted
  // as part of the component or not when the component exists.
  //
  // This example shows the difference between the two flags for two of these
  // delimited components that is present (the port and query) and one that
  // isn't (the reference). The components that this flag affects are marked
  // with a *.
  //                 0         1         2
  //                 012345678901234567890
  // Example input:  http://foo:80/?query
  //              include_delim=true,  ...=false  ("<-" indicates different)
  //      SCHEME: 0                    0
  //    USERNAME: 5                    5
  //    PASSWORD: 5                    5
  //        HOST: 7                    7
  //       *PORT: 10                   11 <-
  //        PATH: 13                   13
  //      *QUERY: 14                   15 <-
  //        *REF: 20                   20
  //
  int CountCharactersBefore(ComponentType type, bool include_delimiter) const;

  // Scheme without the colon: "http://foo"/ would have a scheme of "http".
  // The length will be -1 if no scheme is specified ("foo.com"), or 0 if there
  // is a colon but no scheme (":foo"). Note that the scheme is not guaranteed
  // to start at the beginning of the string if there are preceeding whitespace
  // or control characters.
  Component scheme;

  // Username. Specified in URLs with an @ sign before the host. See |password|
  Component username;

  // Password. The length will be -1 if unspecified, 0 if specified but empty.
  // Not all URLs with a username have a password, as in "http://me@host/".
  // The password is separated form the username with a colon, as in
  // "http://me:secret@host/"
  Component password;

  // Host name.
  Component host;

  // Port number.
  Component port;

  // Path, this is everything following the host name, stopping at the query of
  // ref delimiter (if any). Length will be -1 if unspecified. This includes
  // the preceeding slash, so the path on http://www.google.com/asdf" is
  // "/asdf". As a result, it is impossible to have a 0 length path, it will
  // be -1 in cases like "http://host?foo".
  // Note that we treat backslashes the same as slashes.
  Component path;

  // Stuff between the ? and the # after the path. This does not include the
  // preceeding ? character. Length will be -1 if unspecified, 0 if there is
  // a question mark but no query string.
  Component query;

  // Indicated by a #, this is everything following the hash sign (not
  // including it). If there are multiple hash signs, we'll use the last one.
  // Length will be -1 if there is no hash sign, or 0 if there is one but
  // nothing follows it.
  Component ref;

  // The URL spec from the character after the scheme: until the end of the
  // URL, regardless of the scheme. This is mostly useful for 'opaque' non-
  // hierarchical schemes like data: and javascript: as a convient way to get
  // the string with the scheme stripped off.
  Component GetContent() const;

  // True if the URL's source contained a raw `<` character, and whitespace was
  // removed from the URL during parsing
  //
  // TODO(mkwst): Link this to something in a spec if
  // https://github.com/whatwg/url/pull/284 lands.
  bool potentially_dangling_markup;

  // This is used for nested URL types, currently only filesystem.  If you
  // parse a filesystem URL, the resulting Parsed will have a nested
  // inner_parsed_ to hold the parsed inner URL's component information.
  // For all other url types [including the inner URL], it will be NULL.
  Parsed* inner_parsed() const { return inner_parsed_; }

  void set_inner_parsed(const Parsed& inner_parsed) {
    if (!inner_parsed_)
      inner_parsed_ = new Parsed(inner_parsed);
    else
      *inner_parsed_ = inner_parsed;
  }

  void clear_inner_parsed() {
    if (inner_parsed_) {
      delete inner_parsed_;
      inner_parsed_ = NULL;
    }
  }

 private:
  Parsed* inner_parsed_;  // This object is owned and managed by this struct.
};

// Initialization functions ---------------------------------------------------
//
// These functions parse the given URL, filling in all of the structure's
// components. These functions can not fail, they will always do their best
// at interpreting the input given.
//
// The string length of the URL MUST be specified, we do not check for NULLs
// at any point in the process, and will actually handle embedded NULLs.
//
// IMPORTANT: These functions do NOT hang on to the given pointer or copy it
// in any way. See the comment above the struct.
//
// The 8-bit versions require UTF-8 encoding.

// StandardURL is for when the scheme is known to be one that has an
// authority (host) like "http". This function will not handle weird ones
// like "about:" and "javascript:", or do the right thing for "file:" URLs.

void ParseStandardURL(const char* url, int url_len, Parsed* parsed);

void ParseStandardURL(const char16* url, int url_len, Parsed* parsed);

// PathURL is for when the scheme is known not to have an authority (host)
// section but that aren't file URLs either. The scheme is parsed, and
// everything after the scheme is considered as the path. This is used for
// things like "about:" and "javascript:"

void ParsePathURL(const char* url, int url_len, bool trim_path_end, Parsed* parsed);

void ParsePathURL(const char16* url, int url_len, bool trim_path_end, Parsed* parsed);

// FileURL is for file URLs. There are some special rules for interpreting
// these.

void ParseFileURL(const char* url, int url_len, Parsed* parsed);

void ParseFileURL(const char16* url, int url_len, Parsed* parsed);

void ParseDevURL(const char* url, int url_len, Parsed* parsed);

void ParseDevURL(const char16* url, int url_len, Parsed* parsed);

void ParseUnknownURL(const char* url, int url_len, Parsed* parsed);

void ParseUnknownURL(const char16* url, int url_len, Parsed* parsed);

void ParseUdpURL(const char* url, int url_len, Parsed* parsed);

void ParseUdpURL(const char16* url, int url_len, Parsed* parsed);

void ParseRtpURL(const char* url, int url_len, Parsed* parsed);

void ParseRtpURL(const char16* url, int url_len, Parsed* parsed);

void ParseSrtURL(const char* url, int url_len, Parsed* parsed);

void ParseSrtURL(const char16* url, int url_len, Parsed* parsed);

void ParseTcpURL(const char* url, int url_len, Parsed* parsed);

void ParseTcpURL(const char16* url, int url_len, Parsed* parsed);

void ParseRtmpURL(const char* url, int url_len, Parsed* parsed);

void ParseRtmpURL(const char16* url, int url_len, Parsed* parsed);

void ParseRtspURL(const char* url, int url_len, Parsed* parsed);

void ParseRtspURL(const char16* url, int url_len, Parsed* parsed);

// Helper functions -----------------------------------------------------------

// Locates the scheme according to the URL  parser's rules. This function is
// designed so the caller can find the scheme and call the correct Init*
// function according to their known scheme types.
//
// It also does not perform any validation on the scheme.
//
// This function will return true if the scheme is found and will put the
// scheme's range into *scheme. False means no scheme could be found. Note
// that a URL beginning with a colon has a scheme, but it is empty, so this
// function will return true but *scheme will = (0,0).
//
// The scheme is found by skipping spaces and control characters at the
// beginning, and taking everything from there to the first colon to be the
// scheme. The character at scheme.end() will be the colon (we may enhance
// this to handle full width colons or something, so don't count on the
// actual character value). The character at scheme.end()+1 will be the
// beginning of the rest of the URL, be it the authority or the path (or the
// end of the string).
//
// The 8-bit version requires UTF-8 encoding.

bool ExtractScheme(const char* url, int url_len, Component* scheme);

bool ExtractScheme(const char16* url, int url_len, Component* scheme);

// Returns true if ch is a character that terminates the authority segment
// of a URL.
bool IsAuthorityTerminator(char16 ch);

// Does a best effort parse of input |spec|, in range |auth|. If a particular
// component is not found, it will be set to invalid.

void ParseAuthority(const char* spec,
                    const Component& auth,
                    Component* username,
                    Component* password,
                    Component* hostname,
                    Component* port_num);

void ParseAuthority(const char16* spec,
                    const Component& auth,
                    Component* username,
                    Component* password,
                    Component* hostname,
                    Component* port_num);

// Computes the integer port value from the given port component. The port
// component should have been identified by one of the init functions on
// |Parsed| for the given input url.
//
// The return value will be a positive integer between 0 and 64K, or one of
// the two special values below.
enum SpecialPort { PORT_UNSPECIFIED = -1, PORT_INVALID = -2 };
int ParsePort(const char* url, const Component& port);

int ParsePort(const char16* url, const Component& port);

// Extracts the range of the file name in the given url. The path must
// already have been computed by the parse function, and the matching URL
// and extracted path are provided to this function. The filename is
// defined as being everything from the last slash/backslash of the path
// to the end of the path.
//
// The file name will be empty if the path is empty or there is nothing
// following the last slash.
//
// The 8-bit version requires UTF-8 encoding.

void ExtractFileName(const char* url, const Component& path, Component* file_name);

void ExtractFileName(const char16* url, const Component& path, Component* file_name);

// Extract the first key/value from the range defined by |*query|. Updates
// |*query| to start at the end of the extracted key/value pair. This is
// designed for use in a loop: you can keep calling it with the same query
// object and it will iterate over all items in the query.
//
// Some key/value pairs may have the key, the value, or both be empty (for
// example, the query string "?&"). These will be returned. Note that an empty
// last parameter "foo.com?" or foo.com?a&" will not be returned, this case
// is the same as "done."
//
// The initial query component should not include the '?' (this is the default
// for parsed URLs).
//
// If no key/value are found |*key| and |*value| will be unchanged and it will
// return false.

bool ExtractQueryKeyValue(const char* url, Component* query, Component* key, Component* value);

bool ExtractQueryKeyValue(const char16* url, Component* query, Component* key, Component* value);

}  // namespace uri
}  // namespace common
